Maintaining catalyst surface area in desiccated reforming



8 Sheets-Sheet 1 L. M. CAPSUTO Feb. 8, 1966 MAINTAINING CATALYST SURFACE AREA IN DESICCATED REFORMING Filed May 15, 1964 8 Sheets-Sheet 2 L. M. CAPSUTO 4 TIME ON STREAM, DAYS ndr'led Recycle Gus TIME ON STREAM, DAYS MAINTAINING CATALYST SURFACE AREA IN DESICGATED REFORMING Feb. 8, 1966 Filed May 15, 1964 L. M. CAPSUTO Feb. 8, 1966 MAINTAINING CATALYST SURFACE AREA IN DESICCATED REFORMING Filed May 15, 1964 8 Sheets-Sheet 5 Effect of PCIFI'ICII Pressure of Wafer 0nd Temperufure on Surface Area PARTIAL PRESSURE WATER mm Hg 0 O A 9 w H. d FI/I ms l 0 W uO O O H .mm m W mC sot .n m A o J m .NWCW w p m w wmo W 0 eE m 8 C .WJIDJWS m m w e .n mmmmm m MUT C d n a F O O O 0 O O O O 0 w 4 3 2 F/GJA 60 8O PARTIAL PRESSURE WATER VAPOR mm Hg SURFACE AREA, M /GRAM Feb. 8, 1966 1.. M. CAPSUTO 3,234,120

MAINTAINING CATALYST SURFACE AREA IN DESICCATED REFORMING Filed May 15, 1964 8 Sheets-Sheet 4 500 I l l 4 Effect of Commercial Aging 3 on Surface Area of Platinum E 400 Reforming Catalysis UJ DC 2 F2 3; & Q PI Feed-Various Nophrhos 3 g 300 Q 055p, Severity to Produce 9O-lO2ON(R+3cc) (\l 2*- J I Q I IO I5 MONTHS Catalyst ATmosphere-AiH-Worer Tofol WorerConrucring Corolysr,

| Z,wf. of Corolysf 2O w r em g of Time of Exposure,Hours- 48 Total Pressure,psig O F/ 6 5 5 30 400 I mm pp 2 z/g rt: |OmmppH O '00 I C 4 D I E so m 25mmppH O E n: zoo-A B :5

100mm mm pp 2 PP E o 250 LL] 800 900 m0 40 M fig TEMPERATURE, F (8 320 M /Gm 0.

350 20 M /Gm 2 F/ 0. 5A 5 4% & 1\

600 700 800 900 I000 TE MPERATURE, F

| M. CAPSUTO 3,234,120

MAINTAINING CATALYST SURFACE AREA IN DESICCATED REFORMING Feb. 8, 1966 8 Sheets-Sheet 5 Filed May 15, 1964 gggggg HHHHH IJ L I mmmm 000005 6 2 000000 222222 HHHHHH WV p pppp pp ppp XA @BI E L //I I O O O 0 0 w m w m m 2410 mmm mmmkmi Om mm wo mm m L. M. CAPSUTO Feb. 8, 1966 8 Sheets-Sheet 6 Filed May 15, 1964 N: owm 3 55 8. E TEEB Q 5 8i @955 22 2 0-2 $08-6 25 08 2mm 5,2 6 96 22 :0 3 *0 wSwww o to S 35 All/\LLOV 8 Sheets-Sheet 8 L. M. CAPSUTO MAINTAINING CATALYST SURFACE AREA IN DESICCATED REFORMING 4 DAYS AFTER DRlERS-BY PASSED Feb. 8, 1966 Filed May 15, 1964 United States Patent 3,234,120 MAINTAINING CA ALY T SURFACE AREA IN DESICCATED REFORMINQ Leon M. Capsuto,'Wootibury, Null, assignor to Socony Mobil OilCompany, Inc, a corporation" of New York Filed May 15,-1964, Ser; No. 367,775 15 Claims. (Cl. 208-138) This application is a continuation of my application, Ser. No. 45,827, filed July 28, 1960, now abandoned.

The present invention relates to the reforming of hydrocarbons,-' particularly a mixture of hydrocarbons boiling in the boiling range of gasoline, and more particularly to the reformingof'hydrocarbons boiling in the boiling range of gasoline at pressures of not more than 400'pounds'per square inch gauge (p.s.i.g.) and preferably of-about 200 p.s.i.g. The present invention is also concerned with the pretreatment of virgin or used particleform solid platinum-group'metal reforming catalyst prior to contacting the reforming catalyst with hydrocarbon to be reformed. By application of the principles of the present invention desiccated reformingof the C to 250 F. fraction of Mid-Continent naphtha has been carried on at 200 p.s.i.g. to produce 10 RSVP. leaded (RA-31cc. TEL) gasoline having an oetane rating of 109 to 111 for on-stream periods of ninety-three days.

Desiecatedreforming as'used herein is the characterization of a reforming operation in which the partial pressure of water vapor in the efilu ent of the reforming unit does not exceed about 0.4 millimeter (mm.) of mercury and preferablythe partial pressure of Water vapor in the effluent of the reforming unit is within the range of about 0.05 to about 0.2 millimeter of mercury.

There have been many discussions of the efiect of the moisture content of recycle gas' upon the activity, selectivity, and yield of reformate produced by contact of naphtha with platinum metal reforming catalyst. Thus, for example, in U.S. Patent No. 2,772,217 the patentees teach' that'refor'ming' catalysts comprising oxides or sul tides of metals of Groups IV, V, VI, VII, and VIII after regeneration contain about 0.2 to 1.0 percent water by weight. The patentes recommend that the regenerated catalystbe dried'toa moisture content of about 0.1 to 0.8 percent by weight in a stripping zone. The moisture content of the gas enteringthe aforesaid stripping zone preferably is maintained above 0.5 mol percent and below about 5 mol percent, preferably about 2-3 mol percent. However, the'1noisture of the catalyst entering the reactor is not the sole source of moisture in the reactor. The information given in this patent indicates that 0.5 percent of water by weight based on the catalyst is equivalent to 0.6 mol percent water in the reaction zone. The catalyst loses about 0.3 percent of water by weight in the reactor. The partial pressure of water in the reactor is further increased bysmall amounts of water in the recycle gas andin thefeed naptha. Consequently, the partial pressure of water in the reactor described in U.S. Patent 2,772,217 is in excess of about 40 mm. of Hgat-200 p.s.i.g. and 7.5 mm. Hg at 25 p'.s.i.g.

The description of the reforming method given in U.S. Patent No. 2,842,482 is of a reforming process in which the recycle gas'contains 0.5 percent by volume of water. This water alone will contribute a partial pres- 3,234,120 Patented Feb. 8, 1966 total pressure is less thany0.4 mm. of Hg and preferably about 0.05 to 0.2 mm. of Hg.

There are three sources of water in the reforming re' action zone. to about 10-15 parts per million (p.p.m.) of water. A concentration of 15 p.p.m. water in the charge naphtha contributes only about 0.08 mm. of Hg tothe total partial pressure of water in the reaction'zon'e at a total reaction zone pressure of 200 p.s.i.g. Arr undried recycle gas will build this up to 0.5-2.0 mm. Hg partial pressure. While this amount of water in the reaction zone vapors does not adversely affect the activity of platinum-group metal reforming catalyst it does produce a lower yield of C reformate by volume from a C to 250 F. E.P. feed than when the partial pressure in the final eflluent of the reforming reaction zone is within the range of 0.05 to 0.2 mm. Hg. The data presented in Table I illustrates the effect of the moisture in the recycle gas upon the yield of CD5 reformate when the charge naphtha contains 10-15 ppm. by weight of water.

TABLE I Feed: C to 270 F. fraction of Mid-Continent naphtha. Reaction zone pressure p.s.i.g Hydrogen-to-naphtha mol ratio 4521 Liquid hourly space velocity v./hr./v 1.0 Severity: Octane No. (Research +3 cc. TEL) 104 Catalyst: 0.6 weight percent platinum, 0.7 weight percent chlorine on alumina support.

Run 1 2 3 4 Water in feed naphtha,

p.p.rn. by weight. 10-15 10-15 10-15 10-15 Partial pressure of water in reaction zone efiluent, mm; Hg. 0. 20-0.'31 0.11-0.16 0.12-0.17 Increased yield of 0 reformate, percent base. 1 3 3 Orr-stream" time, day's..- 50 45 63 50 It will be observed that the foregoing data: establish that by reducing the moisture content of the reaction" zone vapors as measured in the final effluent thereof about 35 percent to about 61 percent from 26 to 31 mm. Hg to 12 to 17 mm. Hg,'

The charge naphtha usually contains up a The moisture content of the recycle gas also adversely affects the yield when producing, C reformate having a leaded (Research+3 ce. TEL) octane rating of 109 to 111 from a C to 250 F; E.P. feed even though the.

moisture content of the feed is only p.p.m. byweight and the catalyst is dried at 900-1000 F. to about 1.21

percent by weight water in excess of that held by the catalyst when dried at 1250 C. (2282 F.). That is to say, when the recycle gas is not dried while introducing feed naptha containing 15 p.p.m. of water aboutsix days are required for the system to come to=equilibrium. On

the other :hand, when the recycle gas is dried and the.

catalyst is dried to less than 1.1% by weight water in excess of that'held by catalyst at 1250" C. the system comes to equilibrium in about 1.5 days. However, al-

though the system reaches equilibrium'in about six days when the recycle gas is not dried, the yield of C reformate continues to be about one percent'by volume dried so that the water in the charge naphtha plus the water .inthe'recycle :gas provides a partial pressure of .less' than the'yieldwhen the recycle gas and catalyst are 2 water in the final efiluent of the reforming reaction zone 1 not in excess of 0.2 mm. Hg. The curves in FIGURES 2A and 2B graphically illustrate these facts.

The curves in FIGURES 2A and 2B representpthe data obtained when producing C reformate having a leaded octane rating of 110 from the C3 to 250 F. fraction of Mid-Continent naphtha under the reforming conditions set forth in Table II.

'perature thereof. The'chlorinecontent of the .catalyst:

is also affected by the moisture content of the gas with which thecatalyst is in contact and the temperature thereof. This is; graphically illustrated by the curves in FIG- URES 3A and 3B. i"

Fresh platinum-metal group. reforming catalyst comprising 0.6 percent by .weight platinum and 0.67 percent by weight chlorinev was contacted with 'air .containing water'in the amounts indicatedat a total pressure of 0 p.s.i.g.-for forty-eight hours at the temperatures desig.-- natedon the curves. The .total amount ofwater with which the catalyst was 'inecontact'du'ring each test was the same .and amounted to twenty percent by weight: of J the .catalyst. It will be .observed that evenrat700 F.

the surface 'area of the catalyst is reduced aboutjfifteen reduced onlya negligible amount by;contact;with gas containing water; at 140mm. Hg partial pressure; On. the other hand; the surface .area of iazcatalyst initially having a surface area of 4320 square meters: per, gram is reduced to less than: 200 square ,meters at 900 F. by.

contact with gas. havinga partial pressure of'water of 60mm. Hg and at 1000 F. by contact. .with gas having a partialpressure .of water: of mm. Hg.

TABLE III Comparison of properties of commercially available platinum reforming catalysts Catalyst Standard A B 0 Platinum, Weight percent" 0.6- 0.72. 0.53- 0.78.

Chlorine, weight percent- 0.7 0.42- 0.01- 0.89.

Fluorine, weight percent 0.0- 0.34- 0.0- 0.0.

Base Alumina..- Alumina ,Silica- Alumina Alumina type Eta Gamma... Eta Gamma Surface area, Mfi/gm... 420 157 132 200.

Crushing strength, lb

Platinum crystallite size: Angstroms. 23 17 20/76. Percent- 100 100. /50.

Reforming activity Standard +20 F. .+5 F Standard Selectivity; do- Standard.. Do.

Dehydrogenation activity 83 100. 1

1 55.1% A1203, 43.9% SiOz. 1

2 Less 10 R.V.P. gasoline than standard; 0 dry gas, and H; yields higher than standard;

- C4 yield greater than standard.

B +=1ncreased reaction temperature=l0wer activity.

TABLE II Catalyst: 0.6% by weight platinum, 0.7% by weight chlorine, alumina support 1 2 hrs. at 450 F. in contact with 1 s.c.i. Hz/hl. plus 2 hrs. at 950 F. in contact with 1 s.c.i. Hr/hr. (H2O in I-I .=0.51 p.p.m. by volume). 2 2 hrs. at 450 F. in contact with 1 s.c.f IIz/hl. plus 2 hrs. at 950F. in contact with l,s.c.f.-H /hr. plus 3 hrs. at 960 F. in contactwith 10 s.c.f. Hg/lli'. (H 0 in H =0.51 p.p.m. by volume).

The, moisture content of the catalyst also plays an important part in the partial pressure of water in the. final efiiuent of the reaction zone. The surface area of the alumina support is affected by the moisture contentof the 'All" commercially available .platin'umgroup'metal. re- V forming catalysts do" not initially have ,the same surface area. However, the loss. in surface area of ;a: catalyst is indicative of its. stabilityfor use'as a reforming catalyst. In addition, surface area is one of the mostreadilymeasured of, the important characteristics of platinumgroup metal reforming catalysts. A'cornparison of the properties of four commercially available platinum re-.-

forming catalysts is provided ll'lsTfibl6 III. r

It will be observed that the surface areas. of. these commercially available catalysts range. from about square:

meters per gram to.420 square meters per gram. It will? also be observed that .the size of:the platinum crystallit'es; varies from 100 percent 17 to 23: Angstroms; .(A.) to fifty percent 20 Angstroms and fifty percent 75 Augstromsu It willalso be notedthat reforming activity'and selectivity areequal. ifor .catalystshaving surface areas of 200' and 420 square meters. per. gram. In contrast the catalyst containing a total of about 0.76 percent'by'weight halogen but a surface area of only 157 square meters per gramrequires a vapor inlet temperature about 20 F F- higherthan that required with the standard catalyst;

to produce reformate having the same leaded octane rating. This is indicative of lower activity. On the other hand, where --the acid sites of the catalyst are produced by silica, the halogen content is negligible and the surface area is only about 132 square meters per gram the catalyst requires a vapor inlet temperature about F. higher than that required with the standard catalyst. However, less R.V.P. gasoline is produced with thesilica-alumina' base catalyst, while theyields of C (3 dry gas, and hydrogen are higher than produced with the standard catalyst.

O'neof the most readily measured characteristics of commercially available catalysts after aging for various intervals in commercial reforming units is surface area. Two platinum-metal reforming catalysts were aged in three different commercial reforming units operating at different severities. Samples were examined after various intervals of from five to thirty-six months. The effect of commercial operation on" various properties of the catalysts were determined; The results for catalyst D are presented in Table IV and for catalyst E in Table V.

TABLE IV 6 readily measured, and is one of the most important measurable characteristicss of the catalyst, pretreatment of the catalyst to' provide a catalyst with maximum surface area when initially contactedwith' the naphtha feed is of paramount-- importance.

The surface area of a platinum-group metal reforming catalyst is very sensitive tothe effect of water in' its environment and to the temperature of that environment as is graphically illustrated in FIGURES 5A and 5B.

In FIGURE 5A the change in surface area With-increased temperature from 700 F. to 1000 F. when the gas with which the catalyst is in contact contains various amounts of water measured as the partial pressure of r water vapor is graphically illustrated. The catalyst treated Was a platinum-group metal reforming catalyst comprising 0.6 percent by Weight of platinum and 0L7 which the surface area of the catalyst remains constant .a-re graphically illustrated.

Efiect of aging in commercial units upon surface area, crystallite size, dehydrogenation activity and reforming activity at 500 p.s.i.g.

Refinery Catalyst 1 2 2 3 1 3 3 D D D D D D D D Age, months Fresh Reforming severity O;N. (R+3 cc;) Pt-,.weight percent 0. 6 Cl, weight percent" 0. 67 Surface area mfi/gr'n'. 454" 10; 1 i Yields 1 Normal 4 rlield Normal Normal Normal ass 1 Relative to dehydrogenation activity for fresh catalyst.

1 Vapor inlettemperatureto reform-standard Mid-Continent naphtha to 98 O .N. (R+3 cc.) at 500 p.s.i.g., 2 LHSV, 10:1 hydrogen:

naphtha rnol ratio.

Normal selectivity compared-to fresh catalyst 4 Lossesin 05+ reformatefrom-2%*byvolume at 97 O.N. (R'+3) to 12% by volume at 103 ON. n+3

TABLE V Refinery Catalyst. 1 2 2 3 1 3 3 E E E E E E E E Age, "months Fresh 5 5 13 19 20 36' Reforming severity, O.N. (R-l-3) 101-102 93-99 90-91 97-100 101-102 97-101 97-101 Pt, weight percent 0.35 0.35 0. 0. 35 0. 35 0. 35 0. 35 0. 35 01, weight percent 0. 43 0'. 26 0. 98 0. 0. 41 0. 10 0. 20 0. 25 Surface area, my /gm" 420 176 168 176 129 107 134 Pt crystallite si 22/120 201113 25 24 /5 85/15 100: 61 79 927 904 916 918 974 919 2.6 -1 4.0 1.4 1.8 1.6 Normal. Normal Normal Normal Normal Normal Normal 1 Relative to dehydrogenation activity for fresh 2 Vapor inlet temperature to reform standard hydrogen: naphtha mol ratio.

a Normal selectivity compared to fresh catalyst.

catalyst Mid-Continent naphtha to 98 ON. (11-1-3 cc.) at 500 p.s.i.g., 2 LE SV, 10:1

Inspection of FIGURE 5A establishes that Whenthe partial pressure of water is 5 mm. Hgthe loss in surface area at temperatures from 700 F. to 900 F. is from about 3.6 percent to percent. On the other hand when the partial pressure of water in the gas or atmosphere surrounding the catalyst is 100 mm. Hg the loss in surface area is from about 23.4 to about 50.6 percent.

75 These values are vgiven in Table VI.

TABLE VI PARTIAL PRESSURE OF WATERfMM. HG:

Temp, F.

Surface area Loss in Percent loss 5 mfi/g-m. Surface area in surface mfl/grn. area FIGURE 5B on the other hand graphically shows that to avoid loss in surface area the moisture content of the. catalyst environment or atmosphere must be correlated with the temperature of the environment. Thus, a cata- 1 lyst which has a surface area of 400 square meters per gram (mF/gm.) cannot be exposed to an atmosphere in which the partial pressure of water is in excess of 5 .mm. Hg at temperatures of 700 F. and greater. On the other hand, a catalyst which has a surface area of 200 mP/ gm. can be exposed to an atmosphere in which the partial pres sure of water is in excess of 100 mm. Hg at temperatures of the order of 875 to 1000 F. without loss in surface area. This knowledge is important to the conditioning of catalyst whether virgin or used.

As shown in Tables IV and V the surface area of plat-' Y inurn-group metal reforming catalyst having initially a surface area of about 450 m. gm. was reduced to about ,178 mF/gin. in five months. In the succeeding thirty-one months the surface area was only reduced about 46 m. /gm. Consequently, it is of greatest importancetoi have the surface area of the catalyst initially as high as concomitant with normal yield so that the loss in surface area will not reduce the surface area to a commercially impractical value in too short a period of time on stream. Accordingly, for use especially in reforming at low pres.- sures of not in excess of 400 p.s.i.g., it is presently preferred to employ a platinum-group metal catalyst having a surface area of at least 200 m. gm. and preferably having a surface area of at least 300 m. gm. In FIGURE 5A line A-B is indicative of the minimum surface'area presently required for acceptable performance of a platinum-groupmetal reforming catalyst, employed 'in low pressure reforming, i.e., asurface area of at least 200 mP/gm. Line 'C D in FIGURE 5A graphically sets the minimum surface' area presently preferred for a platinunr'E group metal reforming used in low pressure, i.e., not ex-.' ceeding 400 p.s.i.g. and preferably. about 50 to 25.0 p.s.i.g., reforming. p

I The dataipresented in FIGURES. SA andSB has been; further summarized in FIGURE 5C. The curves in FIG-: URE 50 indicate :the temperatures at which platinum.

group metal reforming catalysts having varioussurfaces can be heated in thepresence of gas having the indicated partial'pressure ofwater '(mm.'Hg) withoutsubstantially Those having V reducing the-surface area'of the catalyst. surface areas of 350 mP/gm. or less can be heatedat temperaturestfronr about: 650 Fito about 870"F; in the presence of gas having a partial pressure of water of mm. Hg without a substantial loss'of: surface area. On

the other hand, catalyst having a surface area in excess of 350 m. /gm. can she heatedto temperatures within the range of about 600 F. to, 1000 F. only in;the presence of gas having a partial pressure of water not in excess of 10 mm. Hg without substantial'loss of surface area.

. The effect of the partial pressure. of water in the feed to a reaction zone :when operating ;to produce a product having an octane rating (R+3 'cc..) of' 109412 from the- C to 250", F. fraction .01? Mid-Continent naphtha is graphically illustrated inFIGUREs6. Itv will be :observed that while the activity of theaplatinum-group metalcatalyst is reduced about 1.5 octane; numbers when the partial pressure of water inthe feed, i.e., naphtha plus hydrogen-containing gas,*to the reaction zone isEincreased from 0.075

.rnm. Hg to 0.115. mm. Hgqthereafter the activity of the catalyst (as measured by the octane rating of the product produced at the same vapor inlet temperature) remains about;the same until the partial pressure of water-imthe feed exceeds5.7 mm. Hg. However,- while the? activity of i the catalyst remains substantially the same theuyieldis reduced about fourtpercent when the partial. pressure of;

water in'the feed,ii.e., naphthaplus recycle. gas,'is increased from 0.155 mm. Hg to 0.25 mm. Hg. A loss of four percent in yield is aloss of-600,000 dollars per year excess of 0.17 mm; Hg in the feedto .a low pressure reforming unit has an immeasurable effect upon the activity of the catalyst thelossin yieldis measurable and of in, dustrial importance.

tha, especially a fraction of naphtha having an end point not exceeding 300 F. and particularly a fraction of naphtha' having ;an end point not exceedingabout 250 F. in

which the partial pressure of water vapor in the vaporou's I contents of. the reforming reaction zone doesnot exceed 0.5 mm. .Hg and preferably .within the range. of not in i.e., in the eflluentiof the last or tail reaction zone.

I Since there are .three sources fromwhich' water is in-g troduced into the reaction zone it follows. that the total amount of'water. introduced from thethreesourcesshould.

not exceed 20.5 mm. Hg :and preferably 0.2 mm; Hg.

Consequently, the-degree to whichthemoisture" content of any of thenaphtha feed, the recycle gas, and the catalyst is reduced grossly is dependent upon .themoisture content of the. other. two. Thus,-for example, it is;.rela-. tively easy'commercially to dry .naphtha to a moisture content of 10 to 15 p.p.m. (parts per'million) by weight of water. This amount of water in the feed of a 10,000

barrels per day (417 barrelsiper hour) 200 p.s.i.g.,reforming unit when the, hydrogen-to-naphtha Inol ratio is;.'-7:1

will provide a partial pressure ,of waterofabout 0.5 to 2.0 mm; Hg in the reaction zone.

originally a surface area of'300 to 400501111016 square least 300 mfi/ gm.

, At this juncture the definitions. of; a few terms used hereinafter and in the claims are given.v

Accordingly, itis an object of they present invention to provide a method-of reforming naph- Hence, the naphtha feed preferably is dried to less than 10 p.p. m. by weight ofwater. The recycle gas generally is dried .not to exceed about 5 ppm. by volume of water. The catalyst having An unconditioned catalyst is avirgin or regenerated particle-form solid platinum-group metal reforming catalyst having a moisture content such that when contacted in a container at 950 F. with gas, i.e., air, or hydrogen, or hydrogen-containing gas consisting essentially of at least 90 percent by volume hydrogen and the balance C to C hydrocarbons, or nitrogemhaving a partial pressureof water of about less than 0.1 mm. Hg at the rate of about 4,200 to about 8,500 s.c.f. of gas/hour/bar'relof catalyst the partial pressure of water in the aforesaid gas is increased to. more than 3-6 mm. Hg as measured at the vapor outlet of said container.

A conditioned catalyst is a virgin or regenerated particle-form solid platinum-group metalzreformin'g catalyst having a moisture content such that when contacted in a container at 950 F. with gas, asdefined herein- 'before, having a partial pressure ofwater oflessthan 0.1 mm. Hg at the'rate of about 4,200 to about 8,500 s.c.f, of gas/hour/barrel of catalyst, the partial pressure of water in thegas as measured at thevapor. outlet of said container. is increased to-less' than about 3-6 mm. Hg;

A conditioned catalyst'is also defined as a virgin or regenerated particle-form solid platinum-group metal: reforming catalyst having a moisture content not more than 1.1 per-centv by weight greater than: the moisture content of the catalyst-before conditioning after. ignition at 1250 C. for 48 hours.

Conditioning is the-oper'ationof contacting aparticle-form solid= platinumvgroup metal reforming catalystwith a dehydrating gas at dehydrating temperature wherein the temperature of the dehydrating gas, as defined hereinafter, is regulated in accordance with the partial pressure of water asmeasured at the vapor outlet of the reaction zone and with the surface area of the aforesaid catalyst prior to conditioning to produce a conditioned catalyst asdefined hereinbefore.

A reaction zone comprises one or more containers each containing a static bed of catalyst with at least one inlet for vaporous and gaseous reactant, and a vapor outlet. The vapor outlet of a reaction zone at which the partial pressure of water is measured when said reaction zone'is established inaa plurality of containers comprising at least a head reactor and" a tail reactoristhe vapor outlet of the-aforesaid tail reactor.

A dehydrating gas is gaswith which unconditioned catalyst, as defined hereinbefore, is contacted to dehydrate or desiccatesaid.unconditioned catalyst to produce conditioned catalyst, A dehydrating gas is nitrogen, fine gas containing not more than fifty percent by volume oxides of carbon, hydrogen, hydrogen-containing gas such as recycle gas comprising hydrogen and C to C hydrocarbons, and air.

A charge naphtha containing innocuous amounts of sulfur, nitrogen, arsenic, and lead is a chargenaphtha containing an amount of sulfur insufiicient to appreciably reduce the activity of the platinum-group metal reforming catalyst and insuflicient to corrodeunduly the ferrous metal with which it is in contact, containing not more than 1 p.p.m. by weight of nitrogen andbeing substantially free of arsenic and lead. Substantially free of 'arsenic and lead designates a concentration of arsenic and/ or lead in a reformer feed which, when said reformerfeed is contacted with a static bed of particle=fornr solid platinum-group metal reforming catalyst comprising about 0.35 percent by weight of platinum, is insufiicient to deactivate said catalyst within the life of the catalyst, for example, two years, as determined by other factors such as the temperature required to produce a reformate having an octane rating of at least 100' (Research+3 cc. TEL), the yield of reformate,-and the mechanical strength of the catalyst.

Platinum-group metal reforming catalyst acts as a desiccant and can absorb up to eight percent by weight 10 of water at atmospheric temperature, humidity, and pressure.

The support of the platinum-group metal reforming catalyst is theportion of the catalyst which acts as a desiccant. Since the support of many particle-form solid' platinum-group metal reforming catalysts is essentially alumina, the characteristics of gamma alumina are indicative of the capabilities-of platinum-group metal catalyst to absorb water'from and to release water to the environment. It is recognized that, when comparing the moisture content of alumina before and after any given treatment, the standard conditions under which the control alumina was dried must be stated for the comparison to be meaningful. Accordingly, the moisture content of alumina which has been heated at 1250 C. in dry air to constant weight is used as a basis of comparison. The amount of water in excess of that present in a sample of alumina ignited at 1250 C. in dry air is designated reversible water. The curves in FIGURE 7 indicate the amount of reversible water absorbed by alumina in contact with air having the indicated partial pressure of water at the indicated temperatures. Accordingly, it is presently preferred to condition a particle-form solid platinum-group metal reforming catalyst having a refractory oxide desiccant base until the moisture of the conditioned catalyst is at such a level that when used to reform naphtha containing not more than 13 ppm. by weight of' water in the presence of recycle gas containing not more than 5 ppm. by volume of water, i.e., partial pressure less than 0.6 mm. Hg, the effluent gas from the reaction zone has a partial pressure of water not in excess of about 0.5 mm. Hg. Presently, it is preferred to condition a particle-form solid platinumgroupmet al reforming catalyst having a base comprising alumina until the aforesaidcatalyst has a moisture'content not more than about 1.1 percent by weight greater than the moisture contentofv the aforesaid catalyst when ignited at 125 C.- In-other words; thereversible'water content of the conditionedcatalystdoes'not exceed 1.1 percent by weight.

Some of. this Water absorbed after the preparation of the catalyst during handlingin and out of the shipping gen to'remove the inert gas and heating-the catalyst to reforming reaction temperature'.- However, anappreciable amount of water is retained .by the catalyst unless a special effort is made to remove the last portion. The water remaining .on the catalyst is given off after the unit goes on-stream. as is evidenced by the moisture content of the recycle gas. (See FIGURES 2A and 2B.) After several days on-streamthe water on the catalyst-equilibrates with the water in the catalyst environment and the water content of the recycle gas drops to a level dependent upon the moisture content of the feed naphtha and the temperature of the liquid-gas separator in which the separation of the recycle gas from the C and heavier reformate is made. The moisture content of saturated recycle gas separated at 70 F. at various pressures is given in Table VII.

TABLE VII Water content of saturated gas 70 F.,.

Pressure, p.s.i.g.: p.p.m. by volume Vapor pressure=18.8 mm. Hg.

graphically in FIGURES 2A and 2B clearly indicate that.

gas containing these amounts of water can have an adverse effect upon the catalyst. On the other hand, in

gas containing 1 ppm. of water by volume the partial Partial pressure of water vapor in gas containing 1. ppm. by volume of Pressure, p.s.i.g.: water, mm. Hg.-

hand, When:the temperature of th'eg' catalyst was raised relatively slowly in the presence. of an ",infinite? volume of gas the surface area of the catalyst in the bottom of.

the reactor was only reduced about 17 percent and onlyj 3 to 7 percent more than the surfaceareas of the catalyst.

in the top and=middle sections respectively of thereactor.

Thus, it is manifest that the.water, removed from the catalyst in onesection of; the reactor has an adverse effect upon catalyst subsequently'contacted with the gas con- 1 taining thetstripped waterwhen the temperature of the 7.60 10- catalyst'in thesubsequently contacted portion ofthe bed 5 5.95 is of the order of950 F. T 200 1.1l 10- The foregoing conclusions are fortified by the data 500 2.70X 10 presented in Table X;

TABLE -X N0. Catalysttreatment Average force to'crush, lbs.

Fresh. ,9. 13: 1. 11 Freshjdried 2 hours at 240 F 8. 41 0.72 Fresh, dried 2 hours at 900F 7. 28d; 0.69 Fresh, heated at 4 FJminute to 000 F., dried 3. 49$ 0. l8

2 hrsat 900 F., cooled in open furnace,-all-in its own atmosphere. Fresh, same as No. 4, except dried air passed 9. 885: 0.49

over the catalyst at 2 space velocity until 4 drying completed. e 6 Fresh, same as No. 5 except hydrogen used in- 10.13i- 0. 51

stead of dried air. e 7 Used butnotregenerated after 276'days prodpcrilglegdedlgasolineh 1lixavling ogtafne traltintg o 1 5 arreso nap apoun o caays; 8 Usedpbut not regenerated after 1 day. on-stream gg ggggfig g value producing leaded. :gasoline having octane y rating of 98; 0.2 barrel of naphtha/pound of catalyst.

The data presented in Table IX clearly establish that control of the moisture of the gas entering the bed of catalyst protects the first section of the bed of catalyst.

However, the Water that the gas removes from the first section of the bed of catalyst will damage each subsequent section of the bedofcatalyst through which pass the gas and water stripped from thepreceding sections of catalyst. Therefore, for protection of the entire bed t of catalyst the moisture content of the gas leaving the bed of catalystmust be controlled.

That is to say, the water content of the gas passing;

through the bottom section of a catalyst bed is equal to the sum of the Water in the gasentering the bed of catalyst'and the water stripped from the preceding sections of the bed of catalyst by the'gas.

TABLE DC Illustrative of the eifect of moisture .in' the recycle gas are the results: graphically presented in FIGURE 8. A C to 270 F. E.P5 fraction of Mid-Continent naphtha was reformed in the presence of platinum-group metal reform-- ing catalyst comprising 0.6 :percent by *weight of'platinum and 0.7 percent-by weight of chlorine on a support com-. prising alumina at-a reactor pressureof 175 p.s.i.g. and

a liquid hourlyspacevelocity 'of 1 toprodu'ce leaded gasolines .having..the octane ratings indicated on the graph. In the first stage the recycle gas was dried to a moisture content of aboutl p.p.m. by volume (.01 mm.'Hg partial pressure of Water). In the second stage the re-- cycle gas'was not driedand contained an average of about:

17.5 ppm. of water '('.2 .min. partial pressure of water). The loss in yield at various octane levels (severi,

Run No Drying temperature, F None (Fresh catalyst) Location of catalyst in reactor:

Top-Surface area,.m. grn Middle-Surface area, mJ/gm- Bottom-Surface area, rnfi/gm- Top-Crushing strength, pounds Middle-Crushing strength, pounds--. Bottom-Crushing strength, pounds Conditions: I

Run N o. 1: 300 to 450 volumes of hydrogen per hour per volume of catalyst for two hours at 450 F., followed by 300 to 450 volumes of hydrogen per hour per volume of catalyst at 950. F., for three hours. Run No. 2: 700 to 1.500 volumes of hydrogen per hour per volume of catalyst for 8 to 30 hours at each of the following temperatures: 80 F., 200 F., 450 F., 700 F., 800 F., 900 F., 1,000

perature of the catalyst raised at a relatively rapid rate the surface area of the catalyst in the bottom of the reactor was reduced by about 51 percent. On the other.

H ties) due to the increasing amount: of Water'in therecycle' gas is plotted against the time in days required for the wet recycle gas to affectthe yields. [Negative change in yield in C reformate: (yield Without driers).]-'.

The effect of the moisture content of the recycle gas 13 upon the yield of leaded gasoline having an octane rating of 110 is graphically illustrated in FIGURES 2A and 2B. The charge stock was the C to 250 F. E.P. fraction of Mid-Continent naphtha dried to a moisture content of 15 p.p.m. by weight. As the moisture content of the recycle gas during a period of about six days decreased from 550 p.p.m. by volume to 150 p.p.m. by volume the yield of C reformate increased from 59 percent by volume to 65 percent by volume. In other words, had the moisture-content of the recycle gas been 150 p.p.m. by volume (1.7 mm. Hg partial pressure of water) initially, the income from a 10,000 barrel a day unit would have been increased $9,000 when producing leaded gasoline having an octane rating of 110.

Thus, all of the data presented hereinbefore clearly establishesithat when a naphtha is reformed in the presence of a platinum-group metal reforming catalyst and hydrogen under a total reactor pressure not exceeding 400 p.s.i.g., 'and preferably not exceeding 200 p.s.i.g., an industrially important increase in yield of the reformate can be obtained by operating under conditions of a reactor pressure of 200 p.s.i.g. such that the vapors in the reforming reaction'zone have a partial pressure of water within the range of 0.10 to 0.20 millimeter of mercury as measured at the vapor outlet of the reforming reaction zone.

Presently, it is preferred to treat all three sources of water to reduce each to a presently practical minimum required for the limiting partial pressure of water in the reaction zone vapors. Thus, the charge naphtha can be dried, if necessary, by means of percolation through salt, contact with solid drying agents such as alumina, molecular sieves,- or by distillation, to a water content of less than about 10 to 15 p.p.m. by weight. The recycle gas is separated from the C and heavier reformate and the cooled gas, when containing more than one to five p.p.m.

of Water at 200 p.s.i.g., i.e., when having a partial pressure of water in excess of .01 to .06 mm. Hg, is dried in any conventional manner as by contact with molecular sieve material [Barrer US. Patent No. 2,306,610 issued Dec. 29, 1942, Linde Air Products,'Co., July 1956, General Information on Linde Molecular Sieves Types 4 A. and 5 A. andLinde Molecular Sieves for Selective Adsorption, March 1956], alumina and the like to a moisture content of not more than 1 p.p.m. by volume at 200 p.s.i.g., i.e., a partial pressure of water of not more than .01 mm. Hg at a total pressure, of 200 p.s.i.g.

Presently, it is preferred to dry, i.e., condition, fresh catalyst by exposing the unconditioned catalyst to 400 volumes per hour of hydrogen per volume of catalyst to 450 F. untilthe partial pressure of water in the exit gas. from the reaction zone is not greater than about 20 mm. Hg. (The hydrogen entering the reaction zone preferably, is dried when necessary to about 1 p.p.m. of water.) When the partial pressure of water in the exit gas from the reaction ZOne (Point A, FIGURE 1) does not exceed- 20 mm. Hg the temperature of the gas and concomitantly the temperature of the catalyst bed is raised to 700 F. The temperature is maintained at 700 F. until the partial pressure of water in the exit gas from the reaction zone (Point A, in FIGURE 1) does not exceed '5 mm. Hg. The temperature of the gas is then raised to 900 F. and held at 900 F. until the partial pressure of water in the exit gas from the reaction zone (Point A, FIGURE 1) does not exceed 1 mm. Hg. In general, after the catalyst has been subjected to the foregoing dehydrating or desiccating treatment the moisture content of the catalyst is low enough that desiccated reforming at 200 p.s.i.g. can be performed when charging a feed naphtha containing not more than about 13 p.p.m. by weight of water and a recycle gas containing not more than 5 p.p.m. of Water by volume, i.e., a partial pressure of water of less than 0.06 mm. Hg. However, when it is desirable or necessary the dehydrating or desiccating treatment can be continued at temperatures of 1000 F. when the partial pressure of water in the exit gas from the reaction zone is not in excess of 1 mm. Hg. However, even in the presence of desiccating inert gas having a partial pressure of water not in excess of 1 mm. Hg, the temperature of the catalyst is not raised above a temperature which is about 20 F. below the temperature at which the platinum-group metal catalyst is irreversibly deactivated.

While the method of dehydrating or desiccating fresh platinum-group metal reforming catalyst given in detail hereinbefore is presently the preferred method for preparing fresh platinum-group metal catalyst for use in reforming naphtha in low reactor pressures, there are many other combinations of time, temperature, and gas rate dependent upon the partial pressure of water in the dchydrating inert gas which can be used. The goal of all catalyst dehydrating treatments is to dehydrate the virgin catalyst to the condition in which after dehydration the partial pressure of water in the dehydrating inert gas when contacted with the desiccated catalyst at the rate of 24 to 240 s.c,f./min./bbl. is not in excess of 1 to 3 mm. Hg under conditions of temperature and partial pressure of water in the dehydrating inertgas (herein-after designated dehydrating gas) that the surface area of the catalyst preferably is not substantially reduced and in general is not reduced to less than about 50 percent.

Yields of C reformate produced at pressures in excess of '400 p.s.i.g., from C naphtha having an end boiling point (E.B.P. or E.P.) within the range of 250 to 270 F. are also improved by dehydrating the platinum-group metal reforming catalyst to the extent described herein- :before. Yields of C reformate produced at pressures from atmospheric to 1000 p.s.i.g. or more from the aforedescribed feeds are improved by dehydrating the platinumgroup metal reforming catalyst to the extent described hereinbefore. Accordingly, the present invention provides a dehydrating procedure for virgin or regenerated platinum-group metal reforming catalyst for use in reforming at pressures from atmospheric to 1000 p.s.i.g. or more. It is to be noted that while the yield of C reformate having an octane rating of 109-111 (R-l-3 cc.) from C to 380 F. E.B;P. naphtha is not improved when operating at pressures not exceeding 400 p.s.i.g. and when the partial pressure of water in the final efiluent does not exceed 0.4 mm. Hg, nevertheless the on-stream time between regenera-tions is increased to practical and economically attractive extent. In general, the dehydration of the platinum-group metal reforming catalyst is carried out by contacting the catalyst with an inert gas such as nitrogen, hydrogen, flue gas containing not more than fifty per cent of oxides of carbon and having a water content in excess of a partial pressure of mm. Hg at temperatures below 700 F. The temperature of the dehydrating gas is increased incrementally as the partial pressure of water in the gas issuing from the reaction zone decreases. Thus, for example, the temperature of the dehydrating gas is maintained below 700 F. until the partial pressure of water in the gas issuing from the reaction zone is less than 100 mm. Hg, for example 50 mm. Hg. The temperature of the dehydrating gas is then raised to 750 F. and held at that temperature until the partial pressure of water in the reaction zone exit gas is less than 50 mm. Hg, for example 10 mm. Hg. The temperature of the dehydrating gas is then raised to 800 F. and held at that temperature until the partial pressure of water in the reaction zone exit gas is less than 10 mm. Hg, for example 5 mm. Hg. The temperature of the dehydrating gas is then raised to at least 900 F. but not greater than about 20 F. less than the heat damaging temperature, i.e., the temperature at which the catalyst is irreversibly deactivated by heat only. The temperature of the dehydrating gas is held at least at 900 F. until the partial pressure of water in the reaction zone exit gas is not more than 1 to 3 mm. Hg.

Reference is now made to FIGURE 1 wherein is illustrated in a diagrammatic manner a reforming unit for reforming naphtha at low reactor pressure, e.g., 200 p.s.i.g.

Reactors R R and R 'are charged with the amount of rating. Thus, for example, a unit to treat 10,000 barrels per day of naphtha at a liquid hourly space velocity of 1 to 4-17 barrels of catalyst. With valve 2 in conduit 1 closed and valve31 in conduit 23 closed, the unit is 1 is charged with a total of 51 tons of catalyst equivalent evacuated to aboutZS inches oflrnercury vacuum. Inert:

gas, e.g.,.nitrogen, is introduced through conduit 27 (valve v32 open) int-o the unit ,to purge the remaining air therefrom through pipe 29. When the concentration of oxy gen in'the inert gasis not greater than about 1 percent the inert gasis displaced with hydrogen or hydrogen-containing gas. The hydrogen Torv hydrogen-containing gas is circulated --by compressor '26 with valves 2 and 30.;a11d

32 closed and valve 31 open. Presently, it is preferred to raise the temperature of the circulating hydrogen-contain-:

ing gas, i.e.,-dehydrating gas, toa'bout 450 F. and-to the dryer. The temperature of the separator 21-i is held at 70 F. or lowerto reduce the load on the driers'. The

lower. thetemperature in the separator the morewater is." condensed and separated in separator 21 and the less.

rated in conjunction with fixed bed driers presently'are preferred. Thus, in general, the. present method of-con-r ditioning platinum-group metal reforming catalysts and particularly platinum-group. metal catalyst having an alumina support provides for dehydrating the catalyst at:

temperatures dependent upon the partial pressure of water in thedehydrating gas'at the vapor outlet of the reaction zone to ensure a minimum reduction in the surface area of the catalyst. Dehydration of thecatalyst in the pres-I ence ofthe dehydrating gas is continued until the partial pressure of water in the dehydratinggas at the vapor out-: let of-the reaction zone is not more than about l to 3 mm.- Hg :whenlc ontacting the catalyst being conditioned with; dehydrating .gas having a partial pressure of water notin excess of 0.06 mm. Hg at the rate of 10 to 10 s.c.f. bf said dehydrating gas per hourv per ton of catalyst equivper barrel .of catalyst '(s.c.f. gas/min./bbl.).

alent to.24240 s.-c.f. of:said dehydrating gas per minute I Illustrative of the advantages accruing'from dehydrat ing or desiccating platinum-group m'etal reforming cata-. lyst in the manner described hereinbefo're and reforming naphtha, particularly the C to 250 F. 'E.P. fraction of naphtha,- at low pressures of atmospheric to 400 p.s.i.g, preferably 100 to 300 p.s.i.g, under desiccated conditions is the following log of such an operation through anim'tial on-stream period, a regeneration, and a second on-stream period during which one-stream periods leaded C reformates' having an octane rating of. 109 to 112 were pro.- duced. Each of the two three months duration.

Feed, 0 to 250* F. E.P. fraction of Mid-Continent naphtha:

Percent by volume on-stream periods were of about q Dehydrating gas: Hydrogen.

Rate of Flow- Time, Temperature F. +s.c.f-gas/ 7 Hours-- 1 Hour/B C" +S .c.f. gas=StandardCubic Feet of Dehydratiug'Gas. *=l3arrel of Catalyst. v

Moisture con- Reaction zone: tent, mm. Hg.

Feed Naphtha (15 Weight p.p.m. H O) 0.8 Recycle .G'asc I I (1 p.p.m. vol.) 1 0.=1 (10 p.p.m. vol) .111 Conditionedcatalysts F.'- 3 mm. 900 Reaction zone pressure, p.s.i.g 20,0

REFORMING CONDITIONS. V

1 Partial Vapor Liquid: Pressure Octane Time On-Strcam, Inlet Hourly, of Water Rating Days 7 Temp Space Undricd R3 cc;

F. Velocity Recycle Gas TEL mm. Hg Gas 1 REGENERATED g 1 Slug of water at 29 days. 2 Slug of water at 53 days.

Thus, it is manifest that the present invention provides.

a novel methodof conditioning virgin or aged, and reerably hydrogen or hydrogen-containing .gas. comprising,

at least 50 percent by volume of hydrogen and the balance 1 to make. percentC to cghydrocarbons, atelevatedtemperaturesnot'in excess of about 1000. Ffdepende'nt upon thej-partial pressure of uwaterin thetvaporo us eflluent of .therreaction zone;..whereindehydrating conditions'of temperatureand partial pressure. of:water in. said reaction'z'one eflluent gas. are regulatedto reducethe loss in surface area of said: reforming catalyst toa minimum not. 3 more than 50' percent of the: surface area of :a.platin'u1ngrouplrnetalfreforrning catalyst having a surface area of erably wherein said dehydrating conditions are regulated to maintain the su face area substantially constant; where-.

. 400 or more square metersper gram (mF/gm.) and tpre'fw in .the' conditioned. platinum-group ;metal reforming .cata- I lyst contains not ,rnore than 1.1 percent by weightofv waterbased upon the weight of the catalyst after-ignition at 1250 C. or when contacted with said dehydrating gas at 950 F. at-the 'rate of 24-240 s.c.f./min.-/bbl. of catalyst the partial pressure of water; in the. gas leaving the catalyst is notamore than 1 to -3 mm. =Hg.; The=-present invention'also provides .a method of: desiccated reforming wherein a charge naphtha containingnot more than innocuous amounts of sulfur, nitrogen: arsenic, and lead is' contacted with particle-form-soli-d platinum-group metal reforming catalyst in areaction zone comprising .one or more chambers ,or reactors; at; pressures ofv 50 to 400 p.s.i.g, preferably to 300 p.s.i.g, at temperatures of at least 900 F. but not more than F. below the catalyst deactivating temperature, at liquid hourly space velocities required to produce 10 R.V.P. leaded gasoline having octane ratings of at least 90 and preferably at least 100, and in the presence of not more than 0.4, preferably 0.1 to 0.2 mm. Hg partial pressure of water measured in the vaporousefiluent of the reaction zone.

Thus, as illustrated by the flow sheet in FIGURE 1, reactors 7, 12, and 17 are charged with a particle-form, solid, platinum-group metal reforming catalyst comprising, for example, about 0.6 percent by Weight of platinum and about 0.7 percent by weight of chlorine on a support comprising alumina. The concentration of platinumgroup-metal is within the limits of 0.1 to about 2 percent by Weight or more. The concentration of chlorine and/or fluorine is within the limits of 0.1 to about 0.8 percent by weight. The'alumina can contain up to 45 percent by weight-of silica and is conventional. The system is exhausted to about inches of mercury vacuum and purged with an inert gas such as nitrogen or flue gas until the concentration of oxygen in the efiiuent gas from reactor 17 is not greater than about 1 percent. After the unit has been purged of air, valve is closed and valve 31 opened. Dehydrating gas, e.g., flue gas containing not more than 50 percent oxides of carbon, nitrogen, hydrogen, or a mixture of hydrogen and C to C hydrocarbons containing at least 50 percent by volume of. hydrogen is introduced into the unit through pipe 27. When the pressure in the unit is about 25 to 200 p.s.i.g. valve 32 is closed and the dehydrating gas is circulated by means of compressor 26. The coolant, usually Water, is introduced into cooler 19 at a temperature and in volume sufficient to coolthe circulating dehydrating gas to at least 70 F. The partially dried dehydrating gas is contacted with suflicient solid absorbent such as 4 to 5 Angstrom molecular sieve material, alumina or other desiccant to reduce the moisture content of the partially dried circulating dehydrating gas to a concentration such that the partial pressure of water in the dehydrating gas is not greater than about .01-.06 mm. Hg.

The circulating dehydrating gas is heated to 450 F. in heaters 5, 10 and 15 and the temperature maintained belowabout 700 F. until the partial pressure of water in the efiluent from reactor 17 is not greater than about 100 mm. Hg. The temperature of the dehydrating gas is then raised to about 700 to about 725 F. until the partial pressure of Water in the efiluent from reaction 17 is not greater than about mm. Hg. The temperature of the dehydrating gas is then raised to about 800 F. to about 825 F. and maintained in that range until the partial pressure of water in the efliuent from reactor 17 is not greater than about 10mm. Hg. The temperature of the dehydrating gas isthen raised to about 950 F. and maintained at that level until the partial pressure of water in the effluent from reactor 17 is not more than 1-to 3 mm. Hg. During the foregoing desiccation of the catalyst the dehydrating gas is circulated through the reactors at the rate of about 24 to about 240 s.c.f./ min./bbl.- of catalyst. During this latter period of conditioning the partial pressure of Water in the circulating dehydrating gas leaving drier 24 is not greater than 0.06 mm. Hg. Alternatively, when the partial pressure of water in the eflluent from reactor 17 is less than 100 mm. Hg the temperature of the dehydrating gas can be raised incrementally from 700-725 F. as the partial pressure of water in the aforesaid efliuent decreases at the rate of about 1.5 to about 1.8 F. per mm. Hg decrease in the partial pressure of water in the aforesaid efliuent.

The catalyst has now been conditioned for desiccated reforming when the concentration of water in the feed naphtha does not exceed 15 p.p.m. by weight and the concentartion of water in the recycle gas is not greater than one p.p.m. at 200 p.s.i.g. (In other words, the Water in the reactors 7, 12, and 17 derived from the catalyst, the feed naphtha, and the recycle gas is not more than 0.4 mm. Hg and preferably within the limits of 0.10 to 0.2 mm. Hg as measured at A in the effluent line of reactor 17.) At this time, when the dehydrating gas is not hydrogen or the aforesaid hydrogen-containing gas the dehydrating gas is displaced with hydrogen or hydrogen-containing'. gas as aforedescribed in which the partial pressure of water is not greater than in the dehydrating gas issuing from drier 2 4 and the pressure in the system raised to operating pressure, in this illustrative example less than 400 p.s.i.g., for example, 200' p.s.i.g. Concomitant with the displacement of a major portion or all of the dehydrating gas other than hydrogen or hydrogen-containing gas the temperature at the vapor inlets of reactors 7, 12, and 17, if necessary, are lowered to operating temperatures and feed naphtha pumped from a source not shown by a pump not shown is introduced through pipe 1 (valve 2 open) into pipe 3 where the feed naphtha mixes with the circulating gas to form a charge mixture in which the hydrogen-to-naphtha mol ratio is about 0.5 :1 to 25:1 and preferably about 3:1 to 10:1.

The charge mixture is heated to reforming reaction temperature in coil 4 in furnace 5 and flows through pipe 6 to reactor '7. The charge mixture flows downwardly through reactor 7 to the vapor outlet thereof and thence through pipe 8 to coil 9 in furnace 10 where the first reactor effluent is reheated to a reforming reaction temperature the same as, or higher or lower than, the reforming reaction temperature as measured at the vapor inlet to reactor 7. The reheated first reactor effiue'nt flows through pipe 11 to reactor 12. The reheated first reactor effluent flows downwardly through reactor 12. The effluent therefrom, the second reactor eflluent, flows from reactor 12 through pipe 13 to coil 14 in furnace 15. In coil 14 the second reactor effluent is reheated to a reforming reaction temperature the same as, higher or lower than the reforming reaction temperatures measured at the inlets of reactors 7 and 12.

The reheated second reactor effluent flows from coil 14 through pipe 16 to reactor 17. The reheated second reactor effluent flows downwardly through reactor 17. The effluent therefrom, the third reactor efiiuent, flows through pipe 18 to cooler 19.

In cooler 19 the third reactor effluent is cooled to a temperature at which water and C and heavier hydrocarbons are condensed. Preferably, the third reactor effiuent is cooled to about 70 F. to balance the load on the driers. The-use of lower cooler temperatures is dependent upon local conditions but the reduced load on the driers usually does not compensate for the increased cost of cooling to appreciably lower temperatures. From cooler 19 the cooled third reactor efiluent flows through pipe 20 to liquid-gas separator 21 where the C and heavier hydrocarbons and water separate from the hydrogen and C to C hydrocarbons.

The C and heavier hydrocarbons are withdrawn from separator 21 through pipe 22 to means for finishing the reformate such as stabilizing, fractionating, the addition of additives, etc. The water flows from separator 21 through pipe 28 to waste.

The hydrogen and C and lighter hydrocarbons cornprise the recycle gas. The recycle gas flows from separator 21 through conduit 23 to drier 24 (valve 31 open). When the volume of recycle gas is in excess of that required to maintain the hydrogen-to-naphtha mol ratio a portion of the recycle gas is bled off to other operations, refinery fuel gas main, or the like.

The partial pressure of water flowing from separator 21 at 70 F. usually is about 15 to 20 mm. Hg. Drier 24 is a plurality of driers some of which are on-stream and some of which are in the regeneration portion of the cycle. To reduce the partial pressure of water in the recycle gas from 20 to .01 mm. Hg requires contact with about 3 to 12 pounds of molecular sieve material (4 to 5 Angstroms) per 10,000 s.c.f. of recycle gasgto be dried to a partial pressure of water. of I01 nim. Hg; 1 Acco'rd ingly, the recycleg'as flows from conduit 23 and contacts about 3 'to' 12 pounds of molecular sieve desiccant per 10,000 s.c. f. of recycle gas. The desiccated recycle :gas

having a. partial pressure of water. of .01 to .06 mm. 'Hg' flows from drier-:24 through conduit 25 to the suction side of compressor 26. Compressor 26 re compresses the desic- 'cated recycle gas to. a pressure somewhat in excess ofthefi pressure. in reactor 7.1 The recompressed desiccatedrecycle gasiflows through conduit'3 to ,coil "4 in'he'ater 5.

taining dehydrating gas at'a rate in therange of about24 to about 240 s.c.f. of hydrogen per; minute per barrel-for about three hours'at a temperature of=at least 950 F. and'vvherein a conditioned particle-form solid platinumgroup metal reformingca-talyst having a surface area of at least300 square meters per gram is obtained;:;

4.:A method of reforming naphtha which comprises-- charging a react-ion zone with 'uncond-itionedparbicle- I form solid platin1nn-group metal re-fiorming catalyst, con tacting said chargedunconditioned partiole form solidpl'atin'um-group metal reforming catalyst Withdehydraming 1 gas, regulating the temperature of said dehydrating gas to .less than 700 F. when the partialipressure of water vapor in said dehydrating gas is in excessof 20 millimeters of mercury, raising the temperature of said dehydrating gas to 700 F.w hen the, partial pressure of watervapor in said dehydrating gas is lessthan 20f but=greater than 5 millimeters of mercury, raising the temperature of said V dehydrating gas to 900 F. whenthe partial pressure of drating gas, regulating the temperature of said dehydrating gas toless than 700 F. when the'partial'pressure of water vapor in said dehydrating .gas is in excess of 20 millimeters of mercury, raising the temperature of said dehydrating 'gas to 700 F. when the rpartialpressure of water vapor I in saiddehydrating gas is less than-20 but greater than a 5 millimeters of mercury, raising the temperature o fsaid dehydrating gas to 900" F. 'When the partial pressure of water vapor in said dehydratinggas does not exceed 5 millimeters of mercury, and maintaining said dehydrating gas at a temperature in the range of 900 to about1000" F. until the partial pressure of water vapor in said dehydrating gas does not exceed 1 millimeter of mercury, all

0t said partial pressures of water vapor in said dehydrat ing gas being measured at the vapor outlet of said reac tion zone.

2. The method of conditioning particle-form solid plati- 1 nurn-group metal reforming catalyst as set forth in claim 1,

wherein the particloform' solid platinum-group metal re forming catalyst comprisesab-out 0.1 to about 2.0 percent by Weight of platinum and about 0.'1 to about 0.8 percent by Weight of chlorine ona support consisting essentially of alumina; wherein the surface area or the unconditioned" particl'e fonn sol-id platinum-group metal reforming cata lyst is at least 350 square meters per gram, wherein said particlegform solid platinum group metal retorming catalyst is contacted with hydrogen-containing dehydrating gas at a temperature of about 450 F., at a rate in the range of about 24 to about 240 s.c.f. of hydrogen per'minute per barrel of catalyst, whereinwhen the partial pressure ot water vapor in said' dehydrating gas is less than 10 millimeters of mercury the temperature of said dehydrating gas raised toat least 700 F., but not substantially in excess of 10009 F., and wherein a conditioned catalyst having a surface area of at least 300 square meters pergram is obtained.

3.The method of conditioning particledorrn solid plati{ mum-group metalretorming catalyst as set forth in claim '1, wherein the particle-form solid platinum-group, metal reforming catalyst comprises about 0.1 to about 2.0 percent by weight of platinum and about0.1 to about 0.8 percent 1 by weight of chlorine. on a support consisting essentially I of alumina, .wherein the surfacearea of the unconditioned particle-form solid platinum-group metal reforming ,cata-.

lyst is at" least 350 square meters per gram, wherein said particle-form solid platinum-group metal reforming catal lyst is contacted with hydrogen-containing dehydrating gas a at a rate in the range of about 24 to about 240 s.c. f. of

hydrogen per minute per barrel of catalyst at a' temperatom of about 45 0? F. for about two hours, wherein when the partial pressure of water vapor in said hydrogenoontaining dehydrating gas is less than 10 millimetersv of E mercury said. particle-form solid platinum-group metal 7 reforming catalyst is contacted with said hydrogen-con- 1 Water vapor inzsaid dehydrating gas does not exceed 5 7 millimeters of mercury, and maintaining a temperature in the range of 900" F1 to: about 1000' F. until the partial :1 pressure of water vapor in said dehydrating gas does not exceed 1 millimeter-of mercury, all of. said pressures of water vapor in said dehydratinggas being meas: ured at the vapor outlet of said reactionv zone, obtaining a conditioned particle-form solid platinum-group metah reforming catalyst,- contacting said conditionedpartiolc form solid platinum-group metalreforming cataiyst'in said reaction zone with charge naphtha in the presence of hydrogen'oontainin'g gas. at reforming :conditions of pressure, temperature, liquid hourly space velocity, and hydrogen-to-naphtha mol ratio; regulating the moisture content of said charge naphtha and said. hydrogen-com 'taining gas to maintain a partial pressure of water vaporin the aforesaid reaction :zone; not in excessof-0.4 milli meter of mercury as measured .at the vapor outletsofth.

aforesaid reaction zone, and recovering .C and heavier reformate having an=,;octane rating appreciably inexcess of the: octanerating otzthe aforesaid chargenaiphtha;

5. A :method of reforming naphtha which comprises charging a reaction zone.with unconditionedparticle I form solid platinum-group metal reforming catalystcomprising about 0.1 to about 2.0-percent .by weight-,of platinum and about 0.1 to about 0.8 percent by weightof chlo rine; on *a support consisting essentially of: alumina-and having a surface area ofat least 350 square; meters per gram, contacting said particle-form solid. platinum-group metal reforming catalyst with hydrogen-containing idehydrating gas at a temperature of about 450 F. atfa rate inthe range of about ,24 to about 240 s.c.f.iof hydrogen.

per minute per barrclof catalyst, iwhen gth, partial pressure of water vapor in: said dehydrating gas-isless than 10 millimeters of mercury raising the; temperature of gas to at least 700 F. buttnotsubstan said dehydrating tially inexcess of l000"F., said partial pressures. of water vapor being measured at thevapor. outlet ofsaid reaction zone, obtaininga conditioned particle-form solid platinum-group metal reforming cata1yst'having- .a surface area of at least 300 square: meters per gram, c0n-' tacting said. conditioned particle-forms platinum-group metal reforming catalyst in said reaction zone, with charge naphtha in the: presence of hydrogen-contain,

ing gas at reforming conditions of pressure, temperature, liquid hourly space :velocity, .andhydrogen-tonaphtha ,mol ratio, regulating the moisture content of said charge naphtha and said ihydrogen-contain ing; gas to maiutainf-a partial pressure of watervapor in the aforesaidmeactionzone not'in-exces's of 0L4' millimeter of mercury as measured at the vapor outlet-ofisaid reaction zone; and recovering C and heavier reformate having an octane rating appreciably in excess of the i octane rating of the aforesaid chargemaphtha.

A method, of reforming naphtha which comprises charging ;a reaction ;zone with .uhconditio'ned particle,

21. fornrsolidplatinum-group metal reforming, catalyst comprising, about 0.35; to about 06 percent by weightof p1ati' num' and-about ;4 to-about. 0.7 percent by weight of chlorine on a support consisting: essentially of alumina and" havingza surfaceaarea of'at least 350 square meters. per: gram, contacting; said: unconditioned particle-form solid platinum-group metal-Jreforming: catalyst with hydrogenacontainin'g.dehydrating.gas at a rate in the range ofi"about-t24 toaabout 240' s.c'.f. of hydrogen per minute pen-barreliofccatalyst. at'a temperature of about 450 F. for about two; hours,wherrthepartial pressure of water vapor'ina said hydrogen containing. dehydrating gas is. less; thar'r -l'O millimeters: .of mercury contacting said particle-form solid platinum-group metal reforming. eatalystiat'a-ratei' in therange of about 24 to about 240 s;c.f.ii-of"hydrogeniper: minute per barrel for about three hours; atia temperature of at least:950 F. but not sub. stantially irrexces's ofvabout 1000' F., obtaining a conditioned; particle-form solid l platinum-group metal reforming catalyst havingwa surface area of. at least 300 square meters per gram, contacting said conditioned particleform solid platinum-group metal reforming catalyst in said reaction zonewith charge naphtha in the presence of hydrogen-containing gas at reforming. conditions of pressure, temperature; liquid hourly space velocity, and hydrog'en-to-naphtha" molratio", regulating the moisture content' of said charge naphtha and said hydrogen-containing gas" to :maintai'rr' a partial pressure of water vapor in the aforesaid reaction 'zone not in excess of 0.4 millimeter of mercury as' measured at the vapor outlet of saidreaction zone, and recovering C and heavier reformate having an octane rating appreciably in excess of the octane rating ofthe aforesaid charge naphtha.

7.'A'rnethod of reforming naphtha which comprises charging a reaction zone with unconditioned particleform solid platinum-group metal reforming catalyst, contacting said charged unconditioned reforming catalyst with dehydrating gas consisting essentially of hydrogen, regulating the temperature and periodically increasing the temperature of the aforesaid dehydrating gas as the partial pressure of Water in the effluent dehydrating gas decreases in accordance with the temperature-partial pressure relation defined by the area upward from the line representing an area of 200 square meters per gram in FIGURE 3A to maintain a surface area of at least 200 square meters per gram of the aforesaid reforming catalyst, obtaining a conditioned particle-form solid platinum-group metal reforming catalyst, contacting said conditioned reforming catalyst in said reaction zone with charge naphtha in the presence of hydrogen-containing gas at reforming conditions of pressure, temperature, liquid hourly space velocity, and hydrogen-to-naphtha rnol ratio, regulating the moisture content of said charge naphtha and said hydrogen-containing gas to maintain a partial pressure of water vapor in the aforesaid reaction zone not in excess of 0.4 millimeter of mercury, and recovering C and heavier reformate having an octane rating appreciably in excess of the octane rating of the aforesaid charge naphtha.

8. The method of reforming as set forth in claim 7 wherein the conditioned particle-form solid platinumgroup metal reforming catalyst has a surface area of at least 300 square meters per gram.

9. A method of reforming naphtha which comprises charging a reaction zone with unconditioned eta-alumina base particle-form solid platinum-group metal reforming catalyst, contacting said charged unconditioned eta-base particle-form solid platinum-group metal reforming catalyst with dehydrating gas consisting essentially of hydrogen, incrementally increasing the temperature of the aforesaid dehydrating gas from about 700 to not more than about 1000 F. as the partial pressure of water in the effluent dehydrating gas decreases in accordance with the temperature-partial pressure relation defined by the area upward of line AB in FIGURE 5A to maintain 22'; a surface area of at least 200 square meters per gram of" theafores'aid reforming catalyst, obtainingaconditioned eta-base particle form'solid platinum-group metal reforming catalyst, contacting said conditioned eta-base'particle- 1 form' solid platinum-groupmeta'l reforming catalyst in said reaction zone with charge naphtha in the presence of hydrogen-containing gas at reforming conditions of.

pressure, temperature, liquid hourly spaceivelocity, and hydrogen-to-naphtha mol ratio, regulating. the moisture content of said charge naphtha'and said hydrogen-comtaining gas to maintain a partial pressure of Water vapor in the foresaid reaction zone notein excess of 0.4'milli= meter of mercury, and recovering C and heavier reform ate having an octane rating appreciably in excess ofthe= octane rating of the aforesaid charge naphtha,

10. The method of reforming naphtha'as set forth'in claim .9 wherein the partial: pressure of water vapor in" the reaction zone isin the range of. 0.05-to. 0,2'millimeter of mercury.

11; A method of reforming naphtha which comprises.

charginga reaction zoneqwith unconditionedparticle form solid platinum-group metal reforming: catalyst, con-, tacting said. charged unconditioned reforming catalyst with dehydrating. gas consisting essentially: of hydrogen, regulating the temperature and periodically increasing the? temperature-of the aforesaid dehydrating gas as the partial pressure of water'in the effluent dehydrating gas decreases in accordance with the temperature-partial pressure relation definedwb'y the area tothe left of the curve: bearing the legend, 200' ml /gm. in FIGURE 513 to maintain a surface area of at'least 200 square meters per gram of. the aforesaid reformingicatalyst, obtaining a conditioned particle-form solid platinum-group metalreforming catalyst, contacting said conditionedreforming catalyst in said reaction zone with charge naphtha in the presence of hydrogen-containing gas at refor-m ing conditions of pressure, temperature, liquid hourly space velocity, and hydrogen-to-naphtha mol ratio, regulating the moisture content of said charge naphtha and said hydrogen-containing gas to maintain a partial pres sure of water vapor in the aforesaid reaction zone not in excess of 0.4 millimeter of mercury, and recovering C and heavier reformate having an octane rating appre ciably in excess of the octane rating of the aforesaid charge naphtha.

12. The method of reforming as set forth in claim 11 wherein the conditioned particle-form solid platinumgroup metal reforming catalyst has a surface area of at least 300 square meters per gram.

13. A method of reforming naphtha which comprises charging a reaction zone with unconditioned particleform solid platinum-group metal reforming catalyst, contacting said charged unconditioned reforming catalyst with dehydrating gas consisting essentially of hydrogen, regulating the temperature and periodically increasing the temperature of the aforesaid dehydrating gas as the partial pressure of water in the effluent dehydrating gas decreases in accordance with the temperature-partial pressure relation defined by the area upward of line CD in FIGURE 5A to maintain a surface area of at least 300 square meters per gram of the aforesaid reforming catalyst, obtaining a conditioned particle-form solid platinum-group metal reforming catalyst, contacting said conditioned reforming catalyst in said reaction zone with charge naphtha in the presence of hydrogen-com taining gas at reforming conditions of pressure, temperature, liquid hourly space velocity, and hydrogen-to naphtha mol ratio, regulating the moisture content of said charge naphtha and said hydrogen-containing gas to maintain a partial pressure of water vapor in the aforesaid reaction zone not in excess of 0.4 millimeter of mercury, and recovering C and heavier reformate having an octane rating appreciably in excess of the octane rating of the aforesaid charge naphtha.

14. A method of reforming naphtha which comprises charging a reaction zone with unconditioned eta-alumina base particle-form solid platinum-group metal reforming, contactingsaid charged unconditioned eta-base particle-form. solid platinum-group metal reforming catalyst."

with dehydrating gas consisting essentially. of hydrogen;

incrementally increasing the temperature of the afore said dehydrating gas from about 700 to not more than about 1000 F. as the partial pressure of water in the effluent dehydrating gas decreases in accordance with the temperature-partial pressure relation definedby the area upward of line CD in FIGURE 5A to maintain a surface area. of at least 300 square meters per gram of the aforesaid reforming catalyst, obtaining a conditioned. eta-based particle-form ,solid'platinum-group metal :re-v

forming catalyst, contacting. said conditioned eta-base :15 particle-form solid platinum-group metal reforming catalyst in said reaction zone with charge naphtha in the t presence of hydrogen-containing gas at reforming conditions of pressure, temperature, liquid hourly space vel'ocity, and hy'drogen-to-naphtha mol ratio, regulating the moisture content of said charge naphtha and said hydrogen-containing gas to maintain'a :partial pressure of water vapor in the aforesaidreaction zone not in excess :of 0.4

millimeter of mercury, and recovering C and heavier'rea formate'haying an octanerating appreciably in .excess ofthe octane ratingof the aforesaid charge naphtha.

- 15.: A method of reformingnaphtha which comprises charging a reaction zone with unconditioned eta-alumina :ba'se particleform solid platinum-group'metal reform 30 ticle-form solid platinum-group metalreforming catalyst ing, contacting said charged unconditioned eta-base parwith dehydrating gasvconsistin'g essentially of hydrogen,

incrementally increasing the temperature of the afore-- said dehydrating gas from about700 to not more than 24' 7 about 1000 F. as the partial :pressure of. water in'zthe. effluent dehydrating gas decreases in accordance with the temperature-partial pressure relation defined by the area upward from the: line representingan area of 200'square meters per gram" in FIGURE? 3A-to maintainasurface area of at least'200 square meters per gram of the-aforesaid reforming catalyst, 'obtaininga conditioned eta-base particle-form solid platinum-group metal reforming cat'- alyst, contacting said conditioned eta-base particle-form; solid platinumrgroup metal "reforming z catalyst tin said reaction zone with charge naphtha in :the' presence, 'of

hydrogen-containing, gas at =.reformin'g conditions ofgpresa sure, temperature, liquid hourly space velocity, and' hydrogen-to-naphtha mol ratio, regulating the: moisturecontent of said charge naphtha and said hydrogen-contain-v ing gas to maintainla partial pressureofwater vaporin the aforesaid reaction zone not in excess of 0.4 millimeter of mercury, and recovering C and heavier reformate having' an octanerating appreciably in excess of the. octane rating of the aforesaid charge naphtha.

References Cited by theEx'aminer UNITEDEQSTATES PATENTS DELBERT E. GANTZ, Primary Examiner.

ALPHONSO D. SULLIVAN, PAUL M. COUGHLAN,

Examiners.

Plank m1 252-455,v 

4. A METHOD OF REFORMING NAPHTHA WHICH COMPRISES CHARGING A REACTION ZONE WITH UNCONDITONED PARTICLEFROM SOLID PLATINUM-GROUP METAL REFORMING CATALYST, CONTACTING SAID CHARGED UNCONDITIONED PARTICLE-FORM SOLID PLATINUM-GROUP METAL REFORMING CATALYST WITH DEHYDRATING GAS, REGULATING THE TEMPERATURE OF SAID DEHYDRATING GAS TO LESS THAN 700*F. WHEN THE PARTIAL PRESSURE OF WATER VAPOR IN SAID DEHYDRATING GAS IS IN EXCESS OF 20 MILLIMETERS OF MERCURY, RAISING THE TEMPERATURE OF SAID DEHYDRATING GAS TO 700*F. WHEN THE PARTIAL PRESSURE OF WATER VAPOR IN SAID DEHYDRATING GAS IS LESS THAN 20 BUT GREATER THAN 5 MILLIMETERS OF MERCURY, RAISING THE TEMPERATURE OF SAID DEHYDRATING GAS TO 900*F. WHEN THE PARTIAL PRESSURE OF WATER VAPOR IN SAID DEHYDRATING GAS DOES NOT EXCEED 5 MILLIMETERS OF MERCURY, AND MAINTAINING A TEMPERATURE IN THE RANGE OF 900*F. TO ABOUT 1000*F. UNTIL THE PARTIAL PRESSURE OF WATER VAPOR IN SAID DEHYDRATING GAS DOES NOT EXCEED 1 MILLIMETER OF MERCURY, ALL OF SAID PARTIAL PRESSURES OF WATER VAPOR IN SAID DEHYDRATING GAS BEING MEASURED AT THE VAPOR OUTLET OF SAID REACTION ZONE, OBTAINING A CONDITIONED PARTICLE-FORM SOLID PLATINUM-GROUP METAL REFORMING CATALYST, CONTACTING SAID CONDITIONED PARTICLEFORM SOLID PLATINUM-GROUP METAL REFORMING CATALYST IN SAID REACTION ZONE WITH CHARGE NAPHTHA IN THE PRESENCE OF HYDROGEN-CONTAINING GAS AT REFORMING CONDITIONS OF PRESSURE, TEMPERATURE, LIQUID HOURLY SPACE VELOCITY, AND HYDROGEN-TO-NAPHTHA MOL RATIO, REGULATING THE MOISTURE CONTENT OF SAID CHARGE NAPHTHA AND SAID HYDROGEN-CONTAINING GAS TO MAINTAIN APARTIAL PRESSURE OF WATER VAPOR IN THE AFORESAID REACTION ZONE NOT IN EXCESS OF 0.4 MILLIMETER OF MERCURY AS MEASURED AT THE VAPOR OUTLET OF THE AFORESAID REACTION ZONE, AND RECOVERING C5 AND HEAVIER REFORMATE HAVING AN OCTANE RATING APPRECIABLY IN EXCESS OF THE OCTANE RATING OF THE AFORESAID CHARE NAPHTHA. 